Hairspring for timepieces



Sept. 11, 1951 w. KOHLHAGEN HAIRSPRING FOR TIMEPIECES Filed April 5,1948 Patented Sept. 11, 1951 HAIRSPKING FOR TIMEPIECES Walter Kohlhagen,Elgin, Ill., assignor to The Ingraham Company, Bristol, 001111., acorporation of Connecticut Application April 5, 1948, Serial No. 18,880

3 Claims. (01. 58-115) The present invention relates to improvements inhairsprings and relates more particularly to improvements in hairspringsfor clocks, watches and other timepieces.

It is the general practice to secure the inner end of a spiralhairspring to a unit comprising a balance-staff and a balance-wheel onthe latter and then prior to the assembly of the unit into a timepiece,vibrating the assembly until the same oscillates at approximately thepredetermined desired rate, whereupon the outer convolution of thehairspring is provided with a kink located adjacent its end and designedto be seated against an anchoring-abutment which usually takes the formof an apertured anchoring-stud.

In assembling hairsprings of the type above referred to in a clockmovement for instance, the outer end of the hairspring is manuallymaneuvered through an aperture in a regulatinglever and then through anaperture in an anchoring-stud. This procedure requires careful handworkand hence is expensive.

Furthermore, since it is the general practice to anchor the outer end ofsuch hairsprings in an aperture in an anchoring-stud by means of awedge, the indiscriminate kinks commonly applied in such hairsprings areapt to be unduly straightened out in the process of driving the wedge inplace. This latter effect results in distortion of the hairspring anderratic behaviour of the timepiece in which it is installed.

One of the main objects of the present invention is to provide asuperior hairspring having a terminal-end which will not materiallyinterfere with its threading through an aperture in a regulating-leveror in an anchoring-stud.

Another object of the present invention is to provide a hairspringhaving a superior terminalend so shaped as to substantially threaditself through apertures in a regulating-lever or ananchoring-stud whenthe balance-unit of which it may form a part is rotated in the directionrequired to move its said outer end toward such apertures.

A further object of the present invention is to provide a superiorhairspring 01' the character referred to having an outer terminal-endwhich not only will not materially interfere with its entry intoapertures of the character referred to but which will also minimize thedistortion of the hairspring when its said terminal-end is anchored inan anchoring-stud or the like.

With the above and other objects in view, as will appear to thoseskilled in the art from the present disclosure, this invention includesall 2 features in the said disclosure which are novel over the priorart.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. 1 is a perspective View of a hairspring embodying the presentinvention and shown as attached at its inner end to a hairspring-collet;

Fig. 2 is a broken face view of a movementframe of a clock showing thehairspring constructed in accordance with the present invention asmounted therein, together with a bah ance-stafl, balance-wheel, bearingsand regulator;

Fig. 3 is an edge view thereof;

Fig. 4 is a broken detail sectional view taken on line 4-4 of Fig. '3but on a larger scale;

Fig. 5 is a broken view on a still larger scale of the outer portion ofthe hairspring shown in conjunction with the anchoring-stud andwedgelike retaining-pin, the anchoring-stud being shown in section andthe retaining-pin being shown as partly inserted into the aperture inthe said anchoring-stud; and

Fig. 6 is a. perspective view of the regulatinglever, detached.

The hairspring illustrated in the accompanying drawings is of spiralform and is generally designated bythe reference character [0. The outerportion of the said hairspring adjacent its extreme end. is bentsubstantially radially inwardly to form a stop-reach H and then is bentagain in the general direction of the curvature of the hairspring toform a terminal-reach l 2. The respective reaches H and I2 are integralwith the hairspring proper It] and the terminal-reach I2 is inclinedoutwardly from the inner end. of the stop-reach ll so that its extremeend occupies the position which is substantially the same radialdistance from the center of the hairspring as is the point of junctureof the stop-reach H with the hairspring proper of which it forms a part.

The inner end of the hairspring I0 is clamped in a collet 13 which, inturn, is tightly fitted upon a balance-staff [4 which, like the collet13, may be of any approved construction. The balancestafi' M has mountedthereon a balance-wheel l5, in a manner usual in so-called marine typeescapement mechanisms.

The respective opposite ends of the balancestafi M are of conicalformand the endv adjacent the hairspring I0 is adapted to oscillate in abearing-stud I5, while the end of the balancestafl nearest thebalance-wheel i'5'is' adapted to oscillate in a bearing-stud H, as isindicated in Fig. 3.

The bearing-stud I6 is mounted in a movement-plate l8 and in a similarmanner the bearing-stud I1 is mounted in a companion movemerit-plate l9between which the unit comprising the parts to [5 inclusive, is adaptedto oscillate. The said movement-plates l8 and iii are held in spacedrelationship with respect to each other by a suitable number of pillarssuch as 20.

Mounted for turning movement against the outer face of themovement-plate l8 and about the bearing-stud I6 as a center, is aregulatinglever generally designated by the reference character 2|. Thesaid regulating-lever is formed with an aperture 22 through which theouter convolution of the hairspring is adapted to pass.-

The width of the aperture 22 is in excess of the length in a radialdirection) of the stop-reach l l of the said hairspring so as to freelypermit the kinked end of the latter to be passed therethrough. 1

Mounted in the movement-plate I8 is a substantially -T-shapedanchoring-stud or -member 23 having its leg or stem extending throughthe said movement-plate inwardly toward the balance-wheel IS. The saidanchoring-stud is rigid- 1y attached to the movement-plate 18 in asuitable manner such, for instance, as by staking the same at 24, as isindicated in Fig. 3. e

The anchoring-stud 23 above referred to is formed with an aperture 25vwhich, like the aperture 22 before referred to, is in circumferentialalignment with the free end of the hairspring it. The width of the saidaperture 25, in a direction radially of the balance-wheel l5 andassociated parts, is slightly in excess of the length of the stop-reachll of the hairspring so as to freely permit the kinked end of the latterto be passed therethrough.

By reference to Figs. 1 and 5 in particular, it will be noted that theextreme end or tip of the inclined terminal-reach 12 of the hairspringi0 is substantially the same radial distance from the center of thebalance-staff M as is the portion of the outer convolution of thehairspring immediately adjacent the radially-outer end of the stopreachI l. The dotted lines 26 in Figs. 1 and 5 are concentric with respect tothe central axis of the collet l3 and the said line 26 serves toindicate the circumferential coincidence of the parts just referred toprior to being stressed, in the manner as will presently appear.

For the purpose of holding the free end of the outer convolution of thehairspring ill anchored in the anchoring-stud 23, a wedge-likeretainingpin may be employed.

After the hairspring ill and its collet l3 have been assembled onto abalance-staff such as l6, such unit will be installed between the movement-plates l8 and i9 so that the opposite ends of the balance-staff Mrespectively freely bear in the bearing-studs I 6 and l'l.- The unit-maynow be turned in a counterclockwise direction (as viewed in thedrawings), whereupon the sloping terminal-reach 12 will pass through theaperture 22 in the regulating-lever 2! with little, if any, directmanual deflection in a radial direction, which deflection may beprovided by a pair of tweezers held by the assembler.

After passing the outer terminal end of the hairspring [0 through theaperture 22 in the regulating-lever 2 i, the continued turning movementof the balance-staff I 4 will cause the inclined terminal-reach l2 ofthe hairspring It! to 4 enter and pass through the aperture 25 in theanchoring-stud 23. The wedge-like retainingpin 2'! may now be insertedinto the aperture 25 from a direction toward the said terminal-end,preparatory to clamping (Fig. 5) the portion of the outer reach of thesaid hairspring lying immediately adjacent the stop-reach I i, againstthe innerwall of the said aperture 25. -The driving in of theretaining-pin 2'! will seat the stop-reach ll against the adjacent faceof the anchoringstud 23, as is indicated in Fig. 5, and a further"straighten out, as is indicated in Fig. 4, until the extreme end of theinclined terminal-reach I2 engages with the inner face of the saidretaining-pin.

The engagement of the extreme end of the terminal-reach l2 with theinner face of the retaining-pin 21, as above described, serves torestrain the stop-reach l I from further straightening out under forceexerted by the driving in of the-said retaining-pin, and thus veryaccurate location of the outer end of the hairspring such as Ill may beachieved uniformly from clock-to-clock.

It will be seen from the foregoing that by so shaping the end of theouter convolution of the hairspring in as to provide the stop-reach l iand the inclined terminal-reach E2 in such relationship that the extremeend of the said terminalreach substantially circumferentially coincideswith the portion of the said outer convolution immediately adjacent theouter end of the stopreach H, the passage of the hairspring throughapertures such as 22 and 25 is not materially interfered with.Furthermore, the stop-reach II is prevented from unduly straighteningout when the retaining-pin 2'! or its equivalent is driven home, by theengagement of the extreme end of the terminal-reach l2 with the saidretaining-pin or its equivalent,

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit and essentialcharacteristics ofthe invention, and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

I claim:

1. A spiral hairspring for timepieces having its outer convolutionkinked to provide a relatively short integral inwardly-extendingstopreach and a terminal-reach integral with the inner end of the saidstop-reach; the said stopreach extending inwardly generally in asubstantially-radial direction and the said terminalreach being inclinedfrom the inner end of said stop-reach outwardly to a point substantiallycoinciding with an imaginary circumferential line touching the junctionof the said stop-reach and the said outer convolution.

2. A hairspring-unit for timepieces comprising a collet; and a spiralhairspring having its inner convolution secured to the said collet andhaving its outer convolution kinked to provide a relatively shortintegral inwardly-extending stopreach and a terminal-reach integral withthe inner end of the said stop-reach; the said stopreach extendinginwardly generally in a substantially-radial direction and the saidterminalreach being inclined from the inner end of said stop-reachoutwardly to. a point substantially coinciding with an imaginarycircumferential line touching the junction of the said stop-reach andthe said outer convolution.

3. An anchorage for a hairspring in a time piece, comprising a kink inan end-convolution of said spring to form therein a laterally-extendingstop-reach and a continuing terminal-reach extending in the generaldirection of said endconvolution; an anchor-member having an aperturethrough which said end-convolution extends with said stop-reach bearingagainst said anchor-member and said terminal-reach extending in totobeyond the latter; and a wedge forced in said aperture in theanchor-member to clamp said end-convolution in place therein, the taper16 2 6 of the forced wedge extending in a direction to hold the clampedportion of said spring convolution in said aperture under sufiicientlongitudinal tension to deflect said reaches toward said wedge and forcethe end of said terminal reach into permanent engagement with saidwedge.

WALTER KOHLHAGEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Putnam July 23, 1940 Number

